1. Field of the Invention
This present invention is directed to blowout preventers; to breech housings for ram blocks for blowout preventers; in certain particular aspects, to movable breech housings which permit easy access to ram blocks therein; and methods of their use.
2. Description of Related Art
The prior art discloses a wide variety of blowout preventers and blowout preventer doors and bonnets.
Typical blowout preventers have selectively actuatable rams with actuators in oppositely disposed portions or bonnets. Doors over these portions or bonnets themselves are movably secured to the body, e.g. with movable bars or with hinges so that a door or bonnet is movable for access and maintenance. The prior art discloses a variety of rams including, but not limited to, pipe rams (to contact, engage, and encompass pipe and/or tools to seal a wellbore); blind rams; multi-rams; and shear rams (to contact and physically shear a pipe or tool in a wellbore). Rams are typically positioned opposite each other on either side of a main body and seal against within the main body upon actuation.
Typical rams include a ram block with various parts, e.g. seals and/or cutting edges or blades. Such seals can be subject to high pressures and to chemical reaction with drilling fluids which can damage the seals. Often rams are inspected or changed out. Prior art systems include a variety of movable doors and bonnets for accessing rams and seals. Blowout preventers are disclosed in many U.S. Patents, including, but not limited to, U.S. Pat. Nos. 3,946,806; 4,043,389; 4,313,496; 4,132,267, 4,558,842; 4,969,390; 4,492,359; 4,504,037; 2,752,119; 3,272,222; 3,744,749; 4,253,638; 4,523,639; 5,025,708; 5,056,418; 5,400,857; 5,575,452; 5,655,745; and 5,918,851.
In many prior art blowout preventers a main body of the blowout preventer is subjected to a variety of stresses and loads, including loads applied to the main body either by or through bonnets or doors and actuators therein. In certain prior art systems these loads have been dealt with by providing relatively massive bodies. One solution to this loading problem has been to make a blowout preventer's main body sufficiently massive that it can adequately deal with any load imposed thereon.
There has long been a need, recognized by the present inventor, for a blowout preventer with easy access to a ram block and for easily moving such a ram block to a position at which it can be inspected and/or replaced.
There has long been a need, recognized by the present inventor for a relatively compact, light weight, relatively inexpensive blowout preventer. There has long been a need for a blowout preventer which effectively and efficiently deals with loads imposed on the blowout preventer and which can be made with relative ease.